The use of optical fibers in communications is growing at an unprecendented rate. Low loss optical fibers which are produced by any of several techniques may be assembled into ribbons which are then assembled into cables, or stranded into cables, or they may be enclosed singularly in a jacket and used in various ways in a central office, or to interconnect computer networks, for example.
In order to assure that the low loss optical fibers which are produced today are not diminished in their effectiveness in systems, the fibers must be connected through intermateable connectors which preserve those low losses. For optical fiber ribbons, connectors comprise grooved chips which hold a plurality of fibers of one ribbon in alignment with fibers of another ribbon. Such a connector is shown for example in U.S. Pat. No. 3,864,018 which issued on Feb. 4, 1975 in the name of C. M. Miller. A connector which is disclosed in U.S. Pat. No. 4,634,214 which issued on Jan. 6, 1987 in the names of T. C. Cannon, et al. is used to connect single optical fibers. In it, a cylindrically shaped plug terminates a single optical fiber and is adapted to be received in a sleeve and adjacent to the plug of another such connector which terminates another single optical fiber.
Minimal loss between the connected fibers is achieved when the optical fibers which are terminated by the plugs are aligned coaxially and when the fiber end faces, each of which is planar, contact in a common plane. Considering the size of the fibers, for example one with a core diameter ranging from 8 to 62.5 microns and a cladding diameter of 125 microns, the task of providing conformable plug and sleeve surfaces in order to meet alignment and end separation requirements is a formidable one.
At relatively high bit rates, separate communications paths are used for transmit and receive links. As a result, a need for a duplex connector which is used to interconnect two optical fibers which provide these paths has developed. The duplex connector which is sought after has provisions for terminating an optical fiber cable which includes two individually buffered optical fibers. Desirably, the sought after duplex connector should be one which is capable of being assembled with another duplex connector and which is capable of being connected to optical devices such as optical data links, for example. Also, provisions should be made for providing a strain relief system to prevent the transfer of undue forces from the cable to the plugs which terminate the optical fibers.
The duplex connector should be capable of being assembled to another duplex connector through a coupling intermediate the two. When the connector is not connected to another connector, provisions must be made to protect plugs which terminate the fibers and which extend from the connector housing for entry into the coupling.
Seemingly, the prior art does not include such a connector. What the prior art does include is a duplex connector which includes a shroud inside a shroud. This fixed arrangement may be suitable for connector-to-connector assemblies, but it precludes the connection of the connector to conventional kinds of optical data links.
What the prior art lacks and what is needed is a duplex optical fiber connector which may be used for connecting two optical fibers to conventional data link assemblies as well as connecting to connector assemblies. Also, the sought after connector includes suitable strain relief provisions as well as provisions for protecting exposed plugs prior to interconnection. Further, the connector should be one in which the plugs are supported in a floating manner so that their position is somewhat adjustable during interconnection. In this way, misalignment of the plugs in the coupling is minimized.